Testing the adaptive efficiency of bitcoin

Abstract

This research aims to investigate an alternative view of market dynamics referred to as the Adaptive Markets Hypothesis which posits that an asset’s efficiency will change over time. As such, this research will test whether Bitcoin is time-varyingly efficient. This will be accomplished in three stages. Firstly, whether Bitcoin returns follow a random walk/martingale will be investigated. If they do, that means that they cannot be predicted, thereby providing evidence of the weak-form market efficiency. If they do not follow a random walk, however, the second phase of the investigation turns to whether they can be modelled. The first attempt models the current Bitcoin return as a function of its own lagged values, which is predicated the idea of all relevant information being reflected in historical returns. The inadequacy of this model in its description of the returns generating process, provides evidence that there is private information that historical returns do not reflect which impacts returns. To account for this, the returns generating process is thus modelled using both historical returns and exogenous lagged variables without need to specify the model’s functional form. If the model performs better in some periods than in others, it can be inferred thus that Bitcoin is timevaryingly efficient.